This invention relates to inspecting textile products such as fabrics of woven, non-woven, knitted or other construction and articles such as garments made therefrom.
Currently, inspection is essentially done by trained hand and eye. Especially in the case of garments, inspection is an intricate and repetitive job, and prone on that account to human error. It is also expensive because of the intensive skilled labour requirement.
"Inspection" can cover a wide range of operations, and a single product can be inspected for a wide variety of faults. Faults for which garments are inspected include dimensional deviations from set standards, non-inclusion or incorrect positioning of trims and components, non-inclusion of stitched seams, incorrect pattern matching, and any of the faults that might be detected in the fabric or fabrics that go to make up the garment which could arise in the manufacture, processing, storage and making up. Fabric itself can be inspected for such things as surface distortions from thin areas resulting from thin yarn, dropped stitches, tuck stitches, broken needles, holes, slub cuts, knot cuts, yarn slubs of unacceptable length, incorrect dimensions, presence of foreign material such as broken needle hooks, colour variation, stains, creases, cracks and barre effects. Inspection for fabric faults should ideally not be left until the garment is inspected, which is wasteful of the labour and additional materials content of the made-up garment.
Techniques exist, of course, for detecting some faults other than by hand and eye. Thin places and holes, for instance, can be detected by sensing photo-optically or otherwise light or other radiation transmitted through a fabric. Broken needle hooks can be detected by passing a fabric over a metal detector. There is currently no general method or universal piece of equipment, however, that can be adapted to detect faults of any description.
But for many inspection processes there is simply no available automatic equipment of any description. One such process is the sizing of garments especially knitted garments such as socks. The sock manufacturing process cannot be controlled so exactly that successive items coming off the same machine are identical in every particular, and this is aggravated where a number of machines produce items to a common nominal size for later pairing, so that two items selected at random from the common delivery of the machine or machines are unlikely to match closely enough to be regarded as a pair.